Pressure ulcers (decubitus) occur relatively often, especially in surgery patients and immobile persons, such as part of the elderly, that have to stay in bed for extended periods. Some parts of the body, e.g. elbows, heels, hips, coccyx, sacrum, scapulae, are affected by the pressure forces exerted by the weight of the body. The seventy of pressure ulcers is classified in various stages. In the first stage, pressure and shearing forces cause pinching of the subcutaneous tissue, occlusion of the capillaries and lymphatics and poor vascularisation in deep tissue layers. Prolonged pressure initiates tissue damage at the skin surface. This results in decreased cell production in the epidermis and thinning of the skin. Blood vessels in the skin are impaired and cause redness. In the second stage, the basal membrane becomes detached from the epidermis. Oedema and blisters occur. In the third stage, the epidermis becomes more and more impaired and the skin surface is also affected. In the further stages, necrosis of deep tissue layers becomes visible on the skin surface. The nutritional condition of decubitus patients is often poor, as a result of insufficient nutrition following surgical operations malnourishment, loss of components from wounds, immobility, physical disability or other impediments.
Prevention and curing of pressure ulcers first of all requires ameliorating extrinsic factors around the wound area, such as reducing the pressure, friction and shear forces, moisture and temperature.
A method of stimulating wound healing by administering zinc, vitamins A and C, selenium, β-carotene and thiamine is disclosed in EP-A-564804. A liquid composition containing 62.5 g/l (25 energy %) of proteins, 34 g/l (30 en.%) of fats and 113 g/l (45 en.%) of carbohydrates may be used. Other vitamins and trace elements may also be present. Pressure ulcers are mentioned among the conditions that would require such enhanced wound healing.
EP-A-367724 discloses immunostimulatory compositions containing, per unit dose (in 1.5 l), 3-40 g (18.75 g) of arginine, 0.1-4 g (1.9 g) of RNA, 0.1-20 g (3 g) of ω-3 polyunsaturated fatty acids (pufa's) comprising 1-2 g of EPA and 0.25-1 g of DHA, and 0.1-20 g (3.6 g) of ω-6 pufa's (linoleic acid). The compositions contain 22 en. % of proteins, 28 en. % of fats and 53 en. % of carbohydrates. Pressure ulcers are not mentioned as conditions for which the immunostimulatory compositions might be useful.
U.S. Pat. No. 5,053,387 discloses a composition for treating traumatic injury, containing arginine (1-3 en. %), intact protein (20-30 en. %), fats (7-15 en. %, containing EPA and linoleic acid with an ω-6/ω-3 ratio of about 1.5) and carbohydrates (65-70 en. %), and further zinc, vitamin A and vitamin C.
A liquid nutritional composition containing arginine for trauma and surgery patients, not including pressure ulcer patients, is disclosed in WO 93/16595. The composition contains 20 en. % of proteins, 24 en. % of fats and 56 en. % of carbohydrates. Arginine accounts for 1-3 en. % of the energy. The ratio of linoleic to α-linolenic acid is between 3.5 and 5.5. The caloric density is 1.2-1.5 kcal/ml and the calorie to nitrogen ratio is between 112 ad 145. The composition further contains vitamins and trace elements in 1 to 2 times the recommended daily amounts.
WO 96/08966 discloses a method of enhancement of wound healing by nitrogen monoxide (NO), which comprises the administration of NO-enhancing compounds such as nitrosyiated amines, antioxidants such as vitamins C and E, and other components such as analgesics. Neither pressure ulcers nor nutritional compositions are contemplated in this document.